A plastic interior material has been mainly used as a surface material of a knob present in an apparatus for controlling transmission gear stages of vehicles. However, this surface material becomes hard and sticky, and thus, improvement of grip feeling has been required.
Polyvinyl chloride (PVC) injection and leather covering injection are applied to the current transmission gear shift (TGS) for improving the grip feeling. However, the PVC material is soft and sticky during injection, and there is a limit to the application of the PVC material due to the generation of substances called endocrine disruptors (environmental hormones). In the case of the natural leather covering, it is disadvantageous because the increase in production cost is excessive due to material costs and the need to incorporate an additional process step.
Replacement of these PVC or natural leather surface materials with thermoplastic polyurethane materials is difficult because one cannot ensure the appearance quality during molding. Moldability is disadvantageous due to the soft feature of the material. In addition, there is a problem in that abrasion resistance and anti-scratch of the surface of the molded material is poor.
There is a method of covering a component after molding the surface by using a powder slush molding (PSM) method, but because the production cost is high and it is vulnerable to scratch, its use is limited to only some components of luxury vehicles.
Therefore, it is desirable to develop new moldable materials that exhibit enhanced properties with respect to grip feeling (texture quality) and durability for use in vehicle interiors.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the present disclosure and therefore it may contain information that does not form part of the prior art that is already known in this field to a person of ordinary skill.